D.I. Kim

Imaging of the Inflammatory Response in Reperfusion Injury after Transient Cerebral Ischemia in Rats : Correlation of Superparamagnetic Iron Oxide-Enhanced Magnetic Resonance Imaging with Histopathology

Background: Acute inflammatory responses have been thought to play a central role in ischemia-reperfusion injury after acute ischemic stroke. Superparamagnetic iron oxide (SPIO) particles have been known to enable in-vivo monitoring of macrophage infiltration by magnetic resonance imaging (MRI) in the experimental ischemic rat brain. Purpose: To determine whether the accumulation of macrophages could be seen in vivo in a reperfusion animal model after focal cerebral ischemia using SPIO-enhanced MRI. Material and Methods: Thirty-four adult male rats were enrolled in this study. SPIO particles were injected into the rats at different time points after 1-hour transient occlusion of the middle cerebral artery, and three-dimensional (3D) T2*-weighted magnetic resonance (MR) images with a gradient-echo sequence were performed 24 hours later. Histochemical iron staining was compared with T2* signal abnormalities. Results: At days 3 and 4 post-reperfusion, focal areas of signal loss indicating local accumulation of SPIO particles appeared in a part of the damaged brain. Areas of signal loss corresponded to local accumulation of iron-laden macrophages in histologic sections, and SPIO-induced signal loss indicated active macrophage transmigration into the reperfused brain. Conclusion: SPIO-enhanced MRI demonstrated through in-vivo monitoring that macrophages participate in reperfusion injury at early stages of injury development. SPIO-enhanced MRI could be a useful tool to examine the inflammatory mechanisms involved in reperfusion brain injury.

Bailout Stent Deployment during Coil Embolization of Intracranial Aneurysms

BACKGROUND AND PURPOSE: Self-expandable stents are an effective tool for coil embolization of wide-neck intracranial aneurysms. The purpose of this study was to assess the feasibility and results of bailout stent positioning during rescue situations after deployment of ≥1 coil. MATERIALS AND METHODS: Among 318 aneurysms treated by coil embolization in 267 patients, 16 patients who were treated by bailout stent deployment were retrospectively reviewed. Bailout procedures were performed to relieve potential parent artery compromise caused by the protruded coil loops or to prevent migration of the unstable coil basket. The size/location of the aneurysm, technical feasibility, successful stabilization rate, and procedure-related complications were evaluated. RESULTS: The locations of the aneurysms were the internal carotid artery (n = 12) and basilar artery (n = 4). The mean aneurysm size was 8.3 mm (range, 3.5–19.4 mm) with hemorrhagic presentation in 3 patients. Relief/prevention of parent artery compromise was achieved by molding the encroached loops back into the sac (n = 11), scaffolding the aneurysmal neck in cases with an unstable coil basket (n = 4), and sidetacking the migrated loop to the parent vessel wall (n = 1). The procedure was technically successful in 87.5% (n = 14). Satisfactory molding or stabilization of the coil was seen in 75% (n = 12). Unsatisfactory molding of the protruded small coil loop was noted in 2 cases of small aneurysms. Acute in-stent thrombosis was successfully managed by thrombolysis (n = 1). CONCLUSIONS: Bailout self-expandable stent deployment may be a feasible and effective method for relief/prevention of parent artery compromise or coil migration caused by prolapsed or unstable coil loops during embolization of aneurysms.

Reconstructive Endovascular Treatment of Intracranial Fusiform Aneurysms: A 1-Stage Procedure with Stent and Balloon

BACKGROUND AND PURPOSE: Intracranial fusiform aneurysms, which incorporate the branch vessel and require salvaging of the parent vessel, are difficult to manage. The goal of this study was to evaluate the efficacy of reconstructive endovascular treatment of intracranial fusiform aneurysms by using a 1-stage procedure with a stent and balloon. MATERIALS AND METHODS: During a 3-year period, 20 patients with 20 intracranial fusiform aneurysms were treated by using a 1-stage procedure involving a balloon and stent. Subarachnoid hemorrhage was present in 15 patients. Five aneurysms were located in the anterior circulation and 15, in the posterior circulation. Clinical outcomes and periprocedural complications were evaluated in all patients. The extent of coil packing was evaluated by control angiography after embolization and classified as either complete occlusion or partial occlusion. Angiography was performed 6, 12, and 24 months after embolization to evaluate stent patency and coil packing. RESULTS: The 1-stage procedure by using a combination of balloon and stent was technically successful in all patients. There were no complications related to the procedure, complete occlusion was obtained in 16 patients, and partial occlusion, in 4 patients. All patients recovered well except for 2 who died due to causes unrelated to the procedure. Clinical follow-up was performed in all surviving patients at a mean of 12.3 months (range, 7–24 months), and angiography showed that the patent parent arteries were free of aneurysm recanalization or in-stent stenosis. CONCLUSIONS: This 1-stage procedure may provide a feasible and safe treatment strategy for the management of intracranial fusiform aneurysms that are not amenable to deconstructive embolization.

Management of Anterior Inferior Cerebellar Artery Aneurysms: Endovascular Treatment and Clinical Outcome

BACKGROUND AND PURPOSE: AICA aneurysms are rare and a challenge to treat surgically. We present our experience of the angiographic results and the clinical outcomes for 9 AICA aneurysms treated by EVT. MATERIALS AND METHODS: Between 1997 and 2009, EVT was attempted for 9 AICA aneurysms. Six patients presented with SAH, and 3 aneurysms were found incidentally. The location of the aneurysms was the proximal AICA in 7 and the distal AICA in 2. Five aneurysms originated from an AICA-PICA variant. Clinical outcomes and procedural complications were evaluated, and angiography was performed 6, 12, and 24 months after embolization to confirm recanalization of the coiled aneurysm. RESULTS: EVT was technically successful in 7 patients (78%). Surgical trapping was performed in 1 patient after failure of EVT, and another aneurysm occluded spontaneously, along with the parent artery during EVT. In 7 patients, the AICAs had good patency on postoperative angiography. Stent-assisted coiling was performed in 3 patients. Follow-up angiographies were performed in 7 patients and showed no evidence of recanalization or progressive occlusion with further thrombosis except in 1 patient. There was no evidence of aneurysm rupture during the follow-up period, and 8 patients were able to perform all usual activities (mRS score, 0–1). CONCLUSIONS: EVT may provide a feasible and safe option as an alternative, though a microsurgical option is initially considered for the management of AICA aneurysms. Further follow-up and more experience are also necessary.

Combination of Multicatheter Plus Stent or Balloon for Treatment of Complex Aneurysms

BACKGROUND AND PURPOSE: Coiling of complex aneurysms is still difficult even with current adjuvant techniques. This study sought to evaluate the safety and effectiveness of a combination of multicatheter plus stent or balloon for the treatment of complex aneurysms. MATERIALS AND METHODS: All complex aneurysms that underwent coiling with the combination technique were identified from prospectively maintained neurointerventional data bases. “Complex aneurysm” was defined as a wide-neck aneurysm with branch incorporation into or a deep lobulation of the sac. The clinical and angiographic outcomes were retrospectively analyzed. RESULTS: Sixty-two complex aneurysms (12 ruptured, 50 unruptured) in 62 patients (mean age, 57 years; male/female ratio, 12:50) were treated with a combination technique by using a multicatheter plus stent (n = 42, 3 ruptured) or balloon (n = 20, 9 ruptured). Treatment-related morbidity (grade 3 hemiparesis) occurred in 1 patient (1.6%). Except for 1 patient who had treatment-related morbidity, none of the other patients with unruptured aneurysms developed new neurologic symptoms at discharge. Nine of the 12 patients with ruptured aneurysms had good outcomes (Glasgow Outcome Score, 4 or 5) at the latest follow-up (mean, 32 months; range, 6–72 months), and 1 patient died from an initial SAH. Posttreatment control angiograms revealed complete occlusion in 27, neck remnant in 34, and incomplete occlusion in 1 aneurysm. At least 1 follow-up catheter or MR angiogram was available in 80.6% (n = 50) (mean, 21 months; range, 6–65 months). There were 4 minor and 3 major recurrences (14.0%). CONCLUSIONS: In this case series, the combination technique by using multicatheter plus stent or balloon seemed safe and effective for the treatment of complex aneurysms.

Development of Mobile Ad Hoc Network for Emergency Telemedicine Service in Disaster Areas

Emergency Telemedicine Service (ETS) is used efficiently for treatment to the wound patient in disaster areas. However, ETS cannot be used if the primary network channel is unavailable due to unexpected damages on the communication infrastructures, and increased network traffics. We established the Mobile Ad hoc Network (MANET) based on Wireless LAN (WLAN), and developed software program implemented with the Ad hoc On-Demand Distance Vector Routing Algorithm. The results of experiment are shown that a Mobile Node (MN) in disaster areas provided the sufficient network bandwidth for ETS using MANET. Therefore, MANET is able to provide the ETS by supple configuring the secondary channel in disaster areas where the primary network channel is unavailable.

Tag detection algorithm for improving the instability problem of an augmented reality

Detection technology is a requirement for an Augmented Reality system. One of the problems with detection technology is the instability problem, which occurs when an obstacle occludes a tag while detecting the tag, and the augmented object suddenly disappears. We have proposed a corner detection algorithm to solve this instability problem. The key feature is that if the tag can recognize its position using its four corner cells despite the obstacle being present, then it can maintain its augmented object. We defined the corner case for all types of cases where the instability problem occurs in ARToolkit or ARTag. We have adapted our proposed algorithm to the corner case in ARToolkit, ARTag and ColorCode vision systems and have compared their false detection rates.

Real-time Ambulance Location Monitoring using GPS and Maps Open API

The term “Open API” has been recently in use by recent trends in social media and web 2.0. It is currently a heavily sought after solution to interconnect Web sites in a more fluid user-friendly manner. We could have benefits easily development and high efficiency.

A usability test of exchanging context in a conference room via mobile device interactions

In a community such as conferences, numerous service providers and service users exist, and people interact using contexts. With the improvements in context-awareness computing and mobile computing technologies, human-computer interactions for exchanging contexts started increasing. In this paper, we introduce some interaction techniques such as tag interaction and service discovery interaction using a mobile device to provide an efficient user interface to exchange contexts in a conference room. We identified typical situations in which these interactions can be used in a paper, poster session, and for providing individual information among the attendees. We analyzed the two interaction techniques to be suitable to improve the interactions for exchanging contexts in a conference.